Fresh, creamy and loaded with flavours, this soup is the first thing I'll make when they officially announce the arrival
of autumn. If you prefer your soup totally smooth – that is, with no textural "interruptions" – forget the sugar snaps.

Deep-fried shallots can be bought in small tubs from many Asian grocers. They are great things to have on stand-by in the
store cupboard for finishing off all manner of salads, soups and other vegetable dishes (not just Thai ones, either), adding
a sweet, oniony aroma as well as a lovely crunch. Serves four.

Bring a pan of salted water to a boil, chuck in the sugar snaps and cook for 90 seconds. Drain, refresh under cold water,
then set aside to drip-dry. Before serving, cut them on an angle into long, thin slices.

Heat the vegetable oil in a large pot and add the sliced onion. Cook, covered, over a low heat for 10-15 minutes, until the
onion is completely soft and sweet.

Stir the red curry paste into the onion, cook for a minute, add the lemongrass, lime leaves, red lentils and water, and
bring up to a boil. Reduce the heat to low and simmer for 15 minutes, until the lentils are lovely and soft.

Remove and discard the lemongrass stalks and lime leaves, then blend the soup until it is smooth. Add the coconut milk, lime
juice and soy sauce, and stir. Put the soup back on the heat. When it is almost boiling, add the sugar snaps, then taste
and adjust the seasoning.

Ladle the hot soup into bowls, scatter some fried shallots on top, if using, and garnish with plenty of fresh coriander and
a squeeze of lime, if you fancy.